Proximity detection based on an electromagnetic field perturbation

ABSTRACT

An apparatus is disclosed for proximity detection based on an electromagnetic field perturbation. In an example aspect, the apparatus includes an antenna array including at least two feed ports and a wireless transceiver coupled to the antenna array. The wireless transceiver is configured to generate an electromagnetic field via the antenna array. The wireless transceiver is also configured to receive energy from the electromagnetic field via the at least two feed ports. The wireless transceiver is additionally configured to adjust a transmission parameter based on the energy received via the at least two feed ports. The transmission parameter varies based on a range to an object that is present within the electromagnetic field.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.62/541,629, filed 4 Aug. 2017, the disclosure of which is herebyincorporated by reference in its entirety herein.

TECHNICAL FIELD

This disclosure relates generally to wireless communication and, morespecifically, to using multiple antenna feed ports to determine aproximity of an object perturbing an electromagnetic field.

BACKGROUND

Cellular and other wireless networks may utilize high frequencies andsmall wavelengths to provide high data rates. In particular, fifthgeneration (5G)-capable devices communicate using frequencies at or nearthe extremely-high frequency (EHF) spectrum with wavelengths at or nearmillimeter wavelengths. Although higher-frequency signals provide largerbandwidths to efficiently communicate large amounts of data, thesesignals suffer from higher path loss (e.g., path attenuation). Tocompensate for the higher path loss, transmit power levels can beincreased or beamforming can concentrate energy in a particulardirection.

Accordingly, the Federal Communications Commission (FCC) has determineda maximum permitted exposure (MPE) limit. To meet targeted guidelines,devices are responsible for balancing performance with transmissionpower and other constraints. This balancing act can be challenging toachieve, especially with devices that have cost, size, and otherconstraints.

SUMMARY

An apparatus is disclosed that implements proximity detection based onan electromagnetic field perturbation. The described techniques sense adisturbance in an electromagnetic field to determine whether an objectis proximate to a computing device. An electromagnetic fieldperturbation that is caused by the object can be detected by analyzingat least two portions of the electromagnetic field that are sensed viaat least two antenna feed ports and a wireless transceiver. A range(e.g., distance) to the object can be determined based on theperturbation. Responsive to proximity detection, a transmissionparameter can be adjusted for wireless communication to enable thewireless transceiver to meet guidelines promulgated by the government orthe wireless industry. The described techniques for proximity detectioncan utilize existing transceiver hardware without introducing additionalsensors.

In an example aspect, an apparatus is disclosed. The apparatus includesan antenna array including at least two feed ports and a wirelesstransceiver coupled to the antenna array. The wireless transceiver isconfigured to generate an electromagnetic field via the antenna array.The wireless transceiver is also configured to receive energy from theelectromagnetic field via the at least two feed ports. The wirelesstransceiver is additionally configured to adjust a transmissionparameter based on the energy received via the at least two feed ports.The transmission parameter varies based on a range to an object that ispresent within the electromagnetic field.

In an example aspect, an apparatus is disclosed. The apparatus includesan antenna array including at least two feed ports and transmissionmeans for generating an electromagnetic field via the antenna array. Theapparatus also includes reception means for receiving energy from theelectromagnetic field via the at least two feed ports. The apparatusadditionally includes adjustment means for adjusting a transmissionparameter based on the energy received via the at least two feed ports.The transmission parameter varies based on a range to an object that ispresent within the electromagnetic field.

In an example aspect, a method for proximity detection based on anelectromagnetic field perturbation is disclosed. The method includesgenerating an electromagnetic field via at least one antenna. The methodalso includes receiving energy from the electromagnetic field via atleast two feed ports, with the at least two feed ports associated withone or more other antennas. The method additionally includes adjusting atransmission parameter based on the energy received via the at least twofeed ports. The transmission parameter varies based on a range to anobject that is present within the electromagnetic field.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example computing device for proximity detectionbased on an electromagnetic field perturbation.

FIG. 2 illustrates an example operating environment for proximitydetection based on an electromagnetic field perturbation.

FIG. 3 illustrates multiple examples of an antenna element for proximitydetection based on an electromagnetic field perturbation.

FIG. 4 illustrates an example antenna array for proximity detectionbased on an electromagnetic field perturbation.

FIG. 5 illustrates an example wireless transceiver and processor forproximity detection based on an electromagnetic field perturbation.

FIG. 6 illustrates an example scheme performed by a proximity detectionmodule for proximity detection based on an electromagnetic fieldperturbation.

FIG. 7 illustrates example perturbation metrics for proximity detectionbased on an electromagnetic field perturbation.

FIG. 8 illustrates an example sequence flow diagram for using proximitydetection based on an electromagnetic field perturbation.

FIG. 9 illustrates example transmission parameter adjustments that aremade in accordance with proximity detection based on an electromagneticfield perturbation.

FIG. 10 is a flow diagram illustrating an example process for proximitydetection based on an electromagnetic field perturbation.

DETAILED DESCRIPTION

An electronic device may use a high transmit power to compensate forpath loss associated with millimeter wave (mmW) signals. Many of theseelectronic devices can be physically operated by a user. Such physicalproximity presents opportunities for radiation to exceed givenguidelines, such as a maximum permitted exposure (MPE) limit asdetermined by the Federal Communications Commission (FCC). Because ofthese issues, it is advantageous to enable devices to detect a proximityof the user.

Some proximity-detection techniques may use a dedicated sensor to detectthe user, such as a camera, an infrared sensor, or a radar sensor.However, these sensors may be bulky and expensive. Furthermore, a singleelectronic device can include multiple antennas that are positioned ondifferent surfaces (e.g., on a top, a bottom, or opposite sides). Toaccount for each of these antennas, multiple cameras or sensors may needto be installed near each of these antennas, which further increases acost and size of the electronic device.

In contrast, techniques for proximity detection based on electromagneticfield perturbations are described herein. The described techniques sensea disturbance in an electromagnetic field to determine whether an objectis proximate to a computing device. An electromagnetic fieldperturbation is determined by analyzing at least two portions of theelectromagnetic field that are sensed via at least two antenna feedports and a wireless transceiver. For example, the portions may be withrespect to different locations, phases, polarizations, or angulardirections of the electromagnetic field. Different antenna elements maybe used to sense the portions, including a dipole antenna, a patchantenna, or a bowtie antenna. In some implementations, a perturbationmetric is computed using the at least two portions. Based on a magnitudeor a phase of the perturbation metric, the object can be detected. Arange (e.g., distance or slant range) to the object can also bedetermined based on the perturbation metric. Responsive to proximitydetection, a transmission parameter can be adjusted for wirelesscommunication to enable the wireless transceiver to meet safetyguidelines promulgated by the government or the wireless industry. Thedescribed techniques for proximity detection offer a relativelyinexpensive approach that can utilize existing transceiver hardwarewithout introducing additional sensors.

In some implementations, the wireless transceiver may be utilized instand-alone proximity-detection applications. For example, the wirelesstransceiver can be implemented as an automotive bumper sensor to assistwith parking or autonomous driving. As another example, the wirelesstransceiver can be installed on a drone to provide collision avoidance.In other implementations, the wireless transceiver can selectivelyperform proximity detection or wireless communication. In such cases,this enables dual-use of components within the transmit and receivechains, which decreases cost and size of the wireless transceiver. Basedon the proximity detection, and as described herein, transmissionparameters can be adjusted for wireless communication to enable thewireless transceiver to meet safety guidelines promulgated by thegovernment or the wireless industry, such as a Maximum PermittedExposure (MPE) limit as determined by the Federal CommunicationsCommission (FCC).

FIG. 1 illustrates an example computing device 102 for proximitydetection based on an electromagnetic field perturbation. In an exampleenvironment 100, the computing device 102 communicates with a basestation 104 through a wireless communication link 106 (wireless link106). In this example, the computing device 102 is implemented as asmart phone. However, the computing device 102 may be implemented as anysuitable computing or electronic device, such as a modem, cellular basestation, broadband router, access point, cellular phone, gaming device,navigation device, media device, laptop computer, desktop computer,tablet computer, server, network-attached storage (NAS) device, smartappliance or other internet of things (IoT) device, medical device,vehicle-based communication system, radio apparatus, and so forth.

The base station 104 communicates with the computing device 102 via thewireless link 106, which may be implemented as any suitable type ofwireless link. Although depicted as a tower of a cellular network, thebase station 104 may represent or be implemented as another device, suchas a satellite, cable television head-end, terrestrial televisionbroadcast tower, access point, peer-to-peer device, mesh network node,small cell node, fiber optic line, and so forth. Therefore, thecomputing device 102 may communicate with the base station 104 oranother device via a wired connection, a wireless connection, or acombination thereof.

The wireless link 106 can include a downlink of data or controlinformation communicated from the base station 104 to the computingdevice 102 and an uplink of other data or control informationcommunicated from the computing device 102 to the base station 104. Thewireless link 106 may be implemented using any suitable communicationprotocol or standard, such as 3rd Generation Partnership ProjectLong-Term Evolution (3GPP LTE), 5th Generation (5G), IEEE 802.11, IEEE802.16, Bluetooth™, and so forth. In some implementations, instead of orin addition to providing a data link, the wireless link 106 maywirelessly provide power and the base station 104 may comprise a powersource.

The computing device 102 includes an application processor 108 and acomputer-readable storage medium 110 (CRM 110). The applicationprocessor 108 may include any type of processor (e.g., an applicationprocessor, a digital signal processor (DSP), or a multi-core processor),that executes processor-executable code stored by the CRM 110. The CRM110 may include any suitable type of data storage media, such asvolatile memory (e.g., random access memory (RAM)), non-volatile memory(e.g., Flash memory), optical media, magnetic media (e.g., disk ortape), and so forth. In the context of this disclosure, the CRM 110 isimplemented to store instructions 112, data 114, and other informationof the computing device 102, and thus does not include transitorypropagating signals or carrier waves.

The computing device 102 may also include input/output ports 116 (I/Oports 116) and a display 118. The I/O ports 116 enable data exchanges orinteraction with other devices, networks, or users. The I/O ports 116may include serial ports (e.g., universal serial bus (USB) ports),parallel ports, audio ports, infrared (IR) ports, and so forth. Thedisplay 118 presents graphics of the computing device 102, such as auser interface associated with an operating system, program, orapplication. Alternately or additionally, the display 118 may beimplemented as a display port or virtual interface, through whichgraphical content of the computing device 102 is presented.

A wireless transceiver 120 of the computing device 102 providesconnectivity to respective networks and other electronic devicesconnected therewith. Additionally, the computing device 102 may includea wired transceiver, such as an Ethernet or fiber optic interface forcommunicating over a local network, intranet, or the Internet. Thewireless transceiver 120 may facilitate communication over any suitabletype of wireless network, such as a wireless LAN (WLAN), peer-to-peer(P2P) network, mesh network, cellular network, wirelesswide-area-network (WWAN), and/or wireless personal-area-network (WPAN).In the context of the example environment 100, the wireless transceiver120 enables the computing device 102 to communicate with the basestation 104 and networks connected therewith.

The wireless transceiver 120 includes circuitry and logic fortransmitting and receiving signals via antennas 124. Components of thewireless transceiver 120 can include amplifiers, mixers, switches,analog-to-digital converters, filters, and so forth for conditioningsignals. The wireless transceiver 120 may also include logic to performin-phase/quadrature (I/Q) operations, such as synthesis, encoding,modulation, decoding, demodulation, and so forth. In some cases,components of the wireless transceiver 120 are implemented as separatetransmitter and receiver entities. Additionally or alternatively, thewireless transceiver 120 can be realized using multiple or differentsections to implement respective transmitting and receiving operations(e.g., separate transmit and receive chains).

The computing device 102 also includes a processor 122, which is coupledto the wireless transceiver 120. The processor 122 can be implementedwithin or separate from the wireless transceiver 120. Although notexplicitly shown, the processor 122 can include a portion of the CRM 110or can access the CRM 110 to obtain computer-readable instructions. Theprocessor 122, which can be implemented as a modem, controls thewireless transceiver 120 and enables wireless communication or proximitydetection to be performed. The processor 122 can include basebandcircuitry to perform high-rate sampling processes that can includeanalog-to-digital conversion, digital-to-analog conversion, Fouriertransforms, gain correction, skew correction, frequency translation, andso forth. The processor 122 can provide communication data to thewireless transceiver 120 for transmission. The processor 122 can alsoprocess a baseband version of a signal obtained from the wirelesstransceiver 120 to generate data, which can be provided to other partsof the computing device 102 via a communication interface for wirelesscommunication or proximity detection.

FIG. 2 illustrates an example operating environment 200 for proximitydetection based on an electromagnetic field perturbation. In the exampleenvironment 200, a hand 214 of a user holds the computing device 102. Inone aspect, the computing device 102 communicates with the base station104 by transmitting an uplink signal 202 (UL signal 202) or receiving adownlink signal 204 (DL signal 204) via the antennas 124. A user'sthumb, however, may represent a proximate object 206 that may be exposedto radiation via the uplink signal 202.

To detect whether the object 206 exists or is within a detectable range,the computing device 102 generates an electromagnetic (EM) field 208 viaat least one of the antennas 124. The electromagnetic field 208 can begenerated by transmitting a predetermined proximity detection signal orthe uplink signal 202. In some cases, the proximity detection signal maybe generated such that it includes a single frequency or tone ormultiple frequencies or tones. For example, the proximity detectionsignal can include an orthogonal frequency-division multiplexing (OFDM)signal having multiple sub-carriers of different frequencies. As anotherexample, the proximity detection signal can include afrequency-modulated continuous wave (FMCW) signal (e.g., a linearfrequency-modulated (LFM) continuous wave signal or chirp signal, atriangular frequency-modulated continuous wave signal, a sawtoothfrequency-modulated continuous wave signal, and so forth). As yetanother example, the proximity detection signal can include acontinuous-wave signal having a relatively constant frequency.

In FIG. 2, a resulting amplitude of the electromagnetic field 208 isrepresented with different shades of grey, where darker shades representhigher amplitudes and lighter shades represent lower amplitudes. If theobject 206 is proximate to another one of the antennas 124, interactionsof the object 206 with the electromagnetic field 208 produce one or moreperturbations (e.g., disturbances or changes) in the electromagneticfield 208, such as perturbation 210. The perturbation 210 represents avariation in a magnitude or phase of the electromagnetic field 208 dueto the object 206 causing different constructive or destructive patternsto occur within the electromagnetic field 208.

In some implementations, the antennas 124 may comprise at least twodifferent antennas, at least two antenna elements 212 of an antennaarray 216, at least two antenna elements 212 associated with differentantenna arrays 216, or any combination thereof. As shown in FIG. 2, theantennas 124 correspond to at least two of the antenna elements 212within the antenna array 216. The antenna array 216 can include multipleantenna elements 212-1 to 212-N, where N represents a positive integergreater than one. In the depicted example, a first antenna element 212-1emits the electromagnetic field 208 and the perturbation 210 is sensedvia a second antenna element 212-2. The second antenna element 212-2 maybe co-located with respect to the first antenna element 212-1 as part ofthe antenna array 216 or otherwise proximate to the first antennaelement 212-1. In some cases, the second antenna element 212-2 isadjacent to the first antenna element 212-1 within a same antenna array216 (e.g., there are no antenna elements 212 physically located betweenthe first antenna element 212-1 and the second antenna element 212-2). Adistance between the antenna elements 212 in the antenna array 216 canbe based on frequencies that the wireless transceiver 120 emits. Forexample, the antenna elements 212 in the antenna array 216 can be spacedby approximately half a wavelength from each other (e.g., byapproximately a centimeter (cm) apart for frequencies around 30 GHz).

A response of the second antenna element 212-2 to the electromagneticfield 208 is affected by the object 206 reflecting or absorbing theelectromagnetic field 208 and also by any mutual coupling orinterference produced by the first antenna element 212-1. In general,energy from the electromagnetic field 208 induces a current in thesecond antenna element 212-2, which is used to measure the perturbation210 or the resulting electromagnetic field 208 that is disturbed by theobject 206. By sensing the perturbation 210, a determination can be madeas to whether the object 206 is present or outside a detectable range(e.g., not present). The detectable range may be within approximately 40cm from the antennas 124, between 0 and 10 cm from the antennas 124, andso forth. In general, the detectable range can vary based ontransmission power or sensitivity of the wireless transceiver 120. Aduration for which the electromagnetic field 208 is generated can alsobe based on the detectable range. Example durations can range fromapproximately one microsecond to several tens of microseconds.

In some cases, the detectable range can include ranges that are notreadily measured using radar-based techniques. For example, theradar-based techniques can be limited to ranges that are farther than aminimum range, which is proportional to a bandwidth of the FMCW signal.Example minimum ranges include 4 cm or 2 cm for a FMCW signal having abandwidth of 4 GHz or 8 GHz, respectively. Therefore, to detect closerdistances using radar-based techniques, the wireless transceiver 120generates larger bandwidth signals at an expense of increased designcomplexity or increased cost of the wireless transceiver 120. Using thedescribed techniques, however, the range to the object 206 can bemeasured at distances closer than these minimum ranges. In this way, thedescribed techniques can be used to augment close-range detection evenif radar-based techniques are used for far-range detection.

In some implementations, the wireless transceiver 120 can generate theelectromagnetic field 208 via the first antenna element 212-1 during asame time that the second antenna element 212-2 is used to sense theelectromagnetic field 208. The antennas 124 and/or elements thereof maybe implemented using any type of antenna, including patch antennas,dipole antennas, bowtie antennas, or a combination thereof, as furtherdescribed with respect to FIGS. 3 and 4.

FIG. 3 illustrates an example antenna element 212 for proximitydetection based on electromagnetic field perturbations and three exampleimplementations thereof. In the depicted configuration (in the top halfof FIG. 3), the antenna element 212 includes multiple feed ports, suchas a first feed port 302 and a second feed port 304. The first andsecond feed ports 302 and 304 separate the response of the antennaelement 212 to the electromagnetic field 208 into multiple portions,such as portions 306 and 308. The multiple portions may be with respectto different locations within the electromagnetic field 208, differentphases of the electromagnetic field 208, different polarizations of theelectromagnetic field 208, different angular directions of theelectromagnetic field 208 (e.g., angles of arrival), and so forth.

These portions 306 and 308 are used for a proximity detection analysis310. A controller 318 can perform the proximity detection analysis 310and an adjustment to a transmission parameter. The proximity detectionanalysis 310, which is further described with respect to FIG. 6, detectsthe object 206 that disturbed the electromagnetic field 208 based on theportions 306 and 308. The controller 318 can include at least oneprocessor and at least one CRM, such as the application processor 108and the CRM 110 of FIG. 1. The CRM can store computer-executableinstructions, such as the instructions 112 of FIG. 1. The processor andthe CRM can be localized at one module or one integrated circuit chip orcan be distributed across multiple modules or chips. Together, aprocessor and associated instructions can be realized in separatecircuitry, fixed logic circuitry, hard-coded logic, and so forth. Thecontroller 318 can be implemented as part of the wireless transceiver120, the processor 122, a special-purpose processor configured toperform MPE techniques, a general-purpose processor, some combinationthereof, and so forth.

Three example antenna elements 212 are also depicted in FIG. 3. Forexample, the antenna element 212 may be implemented using a dipoleantenna 312, which includes a pair of differential feed ports (e.g., apositive (+) feed port 302-1 and a negative (−) feed port 304-1). Inthis case, the portions 306 and 308 are differential portions that areout-of-phase with respect to each other (e.g., differ by approximately180 degrees). As another example, the antenna element 212 may beimplemented using a patch antenna 314, which includes ahorizontally-polarized feed port 302-2 and a vertically-polarized feedport 304-2. Using the patch antenna 314, the portions 306 and 308 haveorthogonal polarities. In other words, the portions 306 and 308respectively represent a horizontally-polarized portion and avertically-polarized portion in this implementation. As yet anotherexample, the antenna element 212 may be implemented using a bowtieantenna 316, which includes feed ports 302-3 and 304-3. In this case,the portions 306 and 308 represent different angular directions of theelectromagnetic field 208 that are sensed along different angles ofarrival.

Although the antenna element 212 is shown to include two feed ports 302and 304, other implementations may generate the multiple portions fromtwo different antenna elements 212 that each include at least one feedport. In general, any two feed ports may be used to produce the portions306 and 308, which are in some way different from each other (e.g., arephysically separate from each other or sense different phases,polarizations, or angles of arrivals). By using multiple feed ports, thedescribed techniques for proximity detection can operate in the presenceof self-generated interference without an extensive calibration processthat characterizes the electromagnetic field 208 (e.g., withoutdetermining a transmit power associated with the electromagnetic field208 or characterizing the mutual coupling between the transmitting andreceiving antenna elements 212).

FIG. 4 illustrates an example antenna array 216 for proximity detectionbased on an electromagnetic field perturbation. In the depictedconfiguration, the antenna array 216 is positioned in an upper-leftcorner of the computing device 102. To detect one or more objects 206(of FIG. 2) that are positioned differently with respect to thecomputing device 102, the antenna array 216 includes a combination offour dipole antennas 312-1, 312-2, 312-3, and 312-4 and four patchantennas 314-1, 314-2, 314-3, and 314-4. The dipole antennas 312-1 and312-2 can be used to detect an object 206 that is near a top 402 of thecomputing device 102 along a vertical direction or Y axis. Likewise, thedipole antennas 312-3 and 312-4 can detect another object 206 that isnear a side 404 of the computing device 102 along a horizontal directionor X axis. The patch antennas can detect an additional object 206 thatis in front 406 of the computing device 102 or above the page along a Zaxis.

In some implementations, a given electromagnetic field 208 (of FIG. 2)may be sensed using a same antenna element 212 or different antennaelements 212. For example, the dipole antenna 312-2 can generate theelectromagnetic field 208 and the dipole antennas 312-1 can sense anyperturbations 210 in the electromagnetic field 208. The dipole antennas312-1 can generate the portions 306 and 308 via the feed ports 302 and304. As another example, the patch antenna 314-2 can generate theelectromagnetic field 208 and the patch antennas 314-1 can generate theportions 306 and 308 via the feed ports 302 and 304.

In other implementations, a given electromagnetic field 208 (of FIG. 2)may be sensed using different antenna elements 212. For example, thedipole antenna 312-2 can generate the electromagnetic field 208 and thedipole antennas 312-1 and 312-3 can respectively generate one of theportions 306 or 308. Alternatively, both dipole antennas 312-1 and 312-3can respectively generate both of the portions 306 and 308 via feedports 302 and 304. As another example, the patch antenna 314-2 cangenerate the electromagnetic field 208 and the patch antennas 314-1 or314-3 can generate one of the portions 306 or 308. Alternatively, bothpatch antennas 314-1 and 314-3 can respectively generate both of theportions 306 and 308.

Different types of antenna elements 212 can also be used to generate orsense the electromagnetic field 208. For example, the dipole antenna312-2 can generate the electromagnetic field 208 and both the dipoleantenna 312-3 and the patch antenna 314-2 can sense at least one of theportions of the electromagnetic field 208. In some cases, both thedipole antenna 312-3 and the patch antenna 314-2 can each sense multipleportions of the electromagnetic field 208. Although not explicitlydepicted, multiple electromagnetic fields 208 may also be generatedsimultaneously. For example, the dipole antennas 312-1 or 312-2 cangenerate an electromagnetic field 208 towards the top 402 of thecomputing device 102 while the patch antennas 314-1, 314-2, 314-3, or314-4 generate another electromagnetic field towards the front 406 ofthe computing device 102.

By utilizing different types of antenna elements 212 or by having theantennas 124 positioned at different locations within or around thecomputing device 102, multiple locations of the object 206 can bemonitored using the described techniques. This further enablestransmission parameters to be independently adjusted relative to whichantenna element 212 detects the object 206. Such independent detectiontherefore enables two or more of the antenna elements 212 to beconfigured for different purposes, for example one of the antennaelements 212 can be configured for enhanced communication performancewhile another one of the antenna elements 212 is simultaneouslyconfigured to comply with FCC requirements. As described in furtherdetail with respect to FIG. 5, some of the components of the wirelesstransceiver 120 can be utilized for both wireless communication andproximity detection.

FIG. 5 illustrates an example wireless transceiver 120 and processor 122for proximity detection based on an electromagnetic field perturbation.The wireless transceiver 120 includes a transmitter 502 and a receiver504, which are respectively coupled between the processor 122 and theantenna array 216. The transmitter 502 is shown to include adigital-to-analog converter (DAC) 506, a filter 508-1 (e.g., a low-passfilter (LPF)), a mixer 510-1, and an amplifier 512-1. Although notexplicitly shown, the transmitter 502 can also include a signalgenerator that is coupled between the digital-to-analog converter 506and the processor 122. The signal generator can generate theelectromagnetic field 208, the proximity detection signal, or the uplinksignal 202.

In the depicted configuration, the transmitter 502 is coupled to a firstfeed port 302-1 of the antenna element 212-1. The first feed port 302-1can comprise, for example, one of the differential feed ports of thedipole antenna 312, one of the polarized feed ports of the patch antenna314, or one of the directional feed ports of the bowtie antenna 316, asshown in FIG. 3. The antenna element 212-1 can also include a secondfeed port 304-2, which is not used in this example.

The receiver 504 is shown to include two parallel receive chains thatare respectively coupled to another first feed port 302-2 and anothersecond feed port 304-2 of the antenna element 212-2. Although a singleantenna element 212 is shown to be coupled to the two receive chains,the two receive chains can alternatively be respectively coupled to twodifferent antenna elements 212, such as the antenna element 212-2 andthe antenna element 212-N or FIG. 2. Each receive chain respectivelyincludes amplifiers 512-2 and 512-3 (e.g., a low-noise amplifier),mixers 510-2 and 510-3, filters 508-2 and 508-3 (e.g., LPFs), andanalog-to-digital converters (ADC) 514-1 and 514-2. The wirelesstransceiver 120 also includes a local oscillator 516, which generates areference signal enabling the mixers 510-1, 510-2, and 510-3 toupconvert or downconvert analog signals within the transmit or receivechains. In some implementations, the local oscillator 516 can include afrequency-modulated local oscillator to generate a frequency-modulatedreference signal that is used to produce a FMCW signal via the mixer510-1 and downconvert a received FMCW signal via the mixers 510-2 and510-3. The transmitter 502 and the receiver 504 can also include otheradditional components that are not depicted in FIG. 5 such as band-passfilters, additional mixers, switches, and so forth.

Using these components, the transmitter 502 generates theelectromagnetic field 208 via the antenna element 212-1, and thereceiver 504 senses the electromagnetic field 208 via the antennaelement 212-2. The response of the antenna element 212-2 to theelectromagnetic field 208 is separated into the portions 306 and 308 viathe feed ports 302-2 and 304-2. The receiver 504 generates digitalsignals Y_(n) ¹ 518-1 and Y_(n) ² 518-2, which can comprise digitalbaseband signal that are derived from the portions 306 and 308,respectively. The digital signals 518-1 and 518-2 may be represented byEquation 1 below, where the electromagnetic field 208 results from atransmitted proximity detection signal x(n).Y _(n) ¹=α₁ x(n)e ^(jφ) ¹ +noise₁Y _(n) ²=α₂ x(n)e ^(jφ) ² +noise₂  Equation 1where α₁ and α₂ are respective amplitudes and φ₁ and φ₂ are respectivephases of the digital signals 518-1 and 518-2. The digital signals canbe affected by any perturbations 210 caused by the object 206 or anymutual coupling that occurs between the first antenna element 212-1 andthe second antenna element 212-2.

The processor 122 performs the proximity detection analysis 310 of FIG.3 based on the digital signals 518-1 and 518-2. In FIG. 5, the processor122 includes at least one proximity detection module 520 and at leastone transmitter control module 524. The proximity detection module 520obtains the digital signals 518-1 and 518-2 and generates detection data522, which indicates whether or not the object 206 is detected. In somecases, the detection data 522 can also include a range to the object206. Based on the detection data 522, the transmitter control module 524generates at least one transmission parameter 526 that controls one ormore transmission attributes for wireless communication. Thetransmission parameter 526 can specify one or more transmission-relatedaspects of the uplink signal 202, such as power level, polarization,frequency, duration, beam shape, beam steering angle, a selected antennathat transmits the uplink signal 202 (e.g., another antenna that is on adifferent surface of the computing device 102 and is not obstructed bythe object 206), combinations thereof, and so forth. By specifying thetransmission parameter 526, the processor 122 can, for example, causethe transmitter 502 to decrease power if an object 206 is close to thecomputing device 102 or increase power if the object 206 is at a fartherrange or is not detectable. The ability to detect the object 206 andcontrol the transmitter 502 enables the processor 122 to balance theperformance of the computing device 102 with compliance. In otherimplementations, the application processor 108 can perform one or moreof these functions.

Although not explicitly shown, multiple antenna elements 212 can be usedto sense additional portions of the electromagnetic field 208 (e.g., athird portion or a fourth portion) and provide multiple pairs of digitalsignals 518 to the processor 122 (e.g., a third digital signal 518 or afourth digital signal 518). For example, two or more of the patchantennas 314 of FIG. 4 may be used to sense the electromagnetic field208 that is generated via one of the other patch antennas 314. In thisway, additional information is provided to the proximity detectionmodule 520 to increase a probability of detecting the object 206 (oraccurately determining a range thereof) and to decrease a probability offalse alarms. The transmitter control module 524 can also make differentadjustments in dependence on whether the object 206 is detected by bothantenna elements 212 or by one of the antenna elements 212.

In some situations, the object 206 may be closer to one of the antennaelements 212, which enables one antenna element 212 to detect the object206 while another antenna element 212 may be unable to detect the object206. In this case, the transmitter control module 524 can decrease atransmit power of the one antenna element 212 relative to the otherantenna element 212. In some implementations, the multiple antennaelements 212 can be used to further characterize the relationshipbetween the object 206 and the antennas 124, such as by estimating anangle to the object 206. In this way, the transmitter control module 524can adjust the transmission parameter 526 to steer the uplink signal 202away from the object 206. Operations of the proximity detection module520 are further described with respect to FIG. 6.

FIG. 6 illustrates an example scheme performed by the proximitydetection module 520 for proximity detection based on an electromagneticfield perturbation. The proximity detection module 520 includes aconjugator 602, a multiplier 604, a low-pass filter (LPF) 606, amagnitude extractor 608, a phase extractor 610, and a detection module612. The conjugator 602 performs a complex conjugate operation on one ofthe digital signals 518, which is the second digital signal 518-2 inthis configuration. The two signals are then multiplied together via themultiplier 604. The low-pass filter 606 filters the resulting signal togenerate a perturbation metric 614. The low-pass filter 606 may beimplemented as an infinite-impulse response (IIR) filter and can removeany spurious frequency components within the resulting signal. Theperturbation metric 614 may be described, at least in part, by Equation2 below.Y _(n) ¹ Y _(n) ²*≅α₁α₂ |x(n)|² e ^(j(φ) ¹ ^(−φ) ² ⁾ =α′e ^(jΔφ)|x(n)|²  Equation 2The perturbation metric 614 can include additional terms not shown inEquation 2 due to operations of the multiplier 604 or low-pass filter606. Although the second digital signal 518-2 is shown to be conjugated,alternatively the first digital signal 518-1 may be conjugated. Inanother example implementation, one of the digital signals 518 can bedivided by the second digital signal 518-2. The resulting perturbationmetric 614 is described in Equation 3, below.Y _(n) ¹ /Y _(n) ²≅α₁/α₂ e ^(j(φ) ¹ ^(−φ) ² ⁾ =α′e ^(jΔφ)  Equation 3

As shown by Equations 2 and 3, the perturbation metric 614 can comprisea complex number having an amplitude α′ and a phase Δφ that result fromcombining the digital signals 518-1 and 518-2 together. The magnitudeextractor 608 and the phase extractor 610 respectively extract theamplitude and the phase of the perturbation metric 614. If more than twoportions of the electromagnetic field 208 are sensed and more than twodigital signals 518 are provided to the processor 122 (e.g., by usingmore than two antenna feed ports), the proximity detection module 520can generate multiple perturbation metrics 614 based on different pairsof digital signals 518. The multiple antenna feed ports can beassociated with a same antenna element 212 or with different antennaelements 212.

Based on the perturbation metric 614, the detection module 612determines whether the object 206 is detected and generates thedetection data 522. The detection data 522 can include a Boolean valueindicating whether the object 206 is detected or is not detected. Thedetection data 522 can also include other information such as the rangeto the object 206 or which antenna elements 212 or antenna feed portswere used to detect the object 206. As described above, the transmittercontrol module 524 can use the detection data 522 to generate thetransmission parameter 526. In some implementations, the components orfunctions of the processor 122 illustrated in FIG. 6 may be included inthe application processor 108. In this case, the digital signals 518 areprovided to the application processor 108. Operations of the detectionmodule 612 are further described with respect to FIG. 7.

FIG. 7 illustrates example perturbation metrics 614 for proximitydetection based on an electromagnetic field perturbation. As describedabove, the perturbation metric 614 can include a complex number, whichhas an in-phase and quadrature component. The perturbation metric 614 isplotted using a triangle or a circle symbol in FIG. 7. With reference tothe key in the top-right corner, the triangle indicates a perturbationmetric 614 that corresponds to a time period for which the object 206 isnot detectable (e.g., the object 206 is not present or is beyond adetectable range). In contrast, the circle indicates a perturbationmetric 614 that corresponds to a time period for which the object 206 isdetectable. Example ranges A, B, C, and D represent different distancesto the object 206 in increasing order (e.g., range A represents smallerdistances and range D represents farther distances). As an example,range A includes distances less than 1 cm, range B includes distancesbetween 1 cm and 2 cm, range C includes distances between 2 cm and 3 cm,and range D includes distances between 3 cm and 5 cm.

A graph 702 plots in-phase and quadrature components of multipleperturbation metrics 614, including perturbation metrics 614-1, 614-2,and 614-3. If the object 206 is not detectable, the perturbation metric614-1 occurs within a window 704, which represents a range of amplitudesor phases. In general, each perturbation metric 614 has a relativelysimilar amplitude and phase if the object 206 is not detectable. This isbecause any perturbations 210 caused by the object 206 generally do notaffect or are not detectable by the antenna element 212. Therefore, theamplitude and phase of the perturbation metric 614 remains relativelyconsistent if no object is within a detectable range.

As the object 206 comes within a detectable range of the wirelesstransceiver 120, however, the in-phase and quadrature components of themultiple perturbation metrics 614 can vary significantly. Theperturbation metrics 614-2 and 614-3 illustrate these variations. Thesevariations occur because the electromagnetic perturbations 210 influencethe magnitude or phase of the electromagnetic field 208 that is sensedby the antenna element 212. Windows 706 and 708 respectively show arange of magnitudes and phases associated with the object 206 beingapproximately within a range A or within a range C from the antennas124. Although not explicitly shown, other windows can also be includedto show the range of magnitudes and phases associated with the object206 being approximately within a range B or within a range D from theantennas 124. In general, multiple perturbation metrics 614 exhibitlarger variations (e.g., are more likely to be dis-similar) the closerthe object 206 is to the antennas 124. Likewise, the multipleperturbation metrics 614 exhibit smaller variations (e.g., are morelikely to be similar) the farther the object 206 is from the antennas124.

Due to the different exhibited characteristics of the perturbationmetric 614, the detection module 612 can use the perturbation metric 614to detect the object 206 or determine the range to the object 206. Inone implementation, the detection module 612 can make the determinationbased on whether the amplitude or phase of the perturbation metric 614is within a predetermined (e.g., pre-defined) window or threshold. Forexample, if the perturbation metric 614 is within the window 704, thedetection module 612 determines that the object 206 is not present or isoutside the detectable range. Alternatively, if the amplitude or phaseis outside the window 704, the detection module 612 can determine thatthe object 206 is proximate to the antennas 124. In some cases, multiplewindows can be used to further determine the range to the object 206.For example, the detection module 612 can determine that the rangecorresponds to the range A or C if the perturbation metric 614 is withinthe window 706 or the window 708, respectively. By determining the rangeto the object 206, the transmitter control module 524 can adjust thetransmission parameters 526 based on the range.

In another implementation, the detection module 612 can recordpreviously-measured perturbation metrics 614 and analyze variations inlater-measured perturbation metrics 614 to determine whether the object206 is present or not. For example, if the perturbation metric 614-1 ispreviously-measured during a known time period for which the object 206is not present, the detection module 612 can compare a later-measuredperturbation metric 614, such as the perturbation metric 614-2 or 614-3,to determine if the object is present. If there is a large amount ofvariation, the detection module 612 can determine that the object 206 ispresent. In other cases, the detection module 612 can compare twoperturbation metrics 614 that are collected using two different antennaelements 212. If the perturbation metrics 614 vary significantly withrespect to each other, then the object 206 may be determined to bepresent with respect to one or both of the antenna elements 212.

FIG. 8 illustrates an example sequence flow diagram for using proximitydetection, with time elapsing in a downward direction. Examples of awireless communication mode are shown at 802 and 806, and examples of aproximity detection mode are shown at 804 and 808. At 802, the wirelesstransceiver 120 transmits a high-power (e.g., normal) uplink signal 202configured to provide sufficient range. After transmitting the uplinksignal 202, the electromagnetic field 208 is generated via the wirelesstransceiver 120 at 804. As described above, the electromagnetic field208 enables the computing device 102 to detect an object 206 anddetermine if the object 206 is near the computing device 102. In thiscase, the electromagnetic field 208 is represented by a low-powernarrow-band signal. Based on the detection, the transmitter controlmodule 524 can generate the transmission parameter 526. In someimplementations, the transmission parameter 526 can be generated for anext uplink signal 202 to account for MPE compliance guidelines. Forexample, if the object 206 is detected, the transmitter control module524 can decrease the transmit power for the next uplink signal 202.Alternatively, if the object 206 is not detected, the transmittercontrol module 524 can keep the transmit power unchanged. In otherimplementations, the transmission parameter 526 can specify transmissionof another electromagnetic field 208 by specifying another antenna or adifferent transmit power level of a next electromagnetic field 208.

The proximity detection mode can also determine the range to the object206, thereby enabling the transmission parameter 526 to comply withrange-dependent guidelines. An example range-dependent guidelineincludes a maximum power density. Power density is proportional totransmit power and inversely proportional to range. Accordingly, for asame transmit power level, an object 206 at a closer range is exposed toa higher power density than another object 206 at a farther range.Therefore, a similar power density at the object 206 can be achieved byincreasing the transmit power level if the object 206 is at a fartherrange and decreasing the transmit power level if the object 206 is at acloser range. In this way, the transmission parameter 526 can beadjusted to enable the power density at the object 206 for both thecloser range and the farther range to be below the maximum powerdensity. At the same time, because the range is known, the transmitpower level can be increased to a level that facilitates wirelesscommunications and comports with the compliance guideline.

At 806, the wireless transceiver 120 transmits the next uplink signal202 using the transmission parameter 526 generated by the transmittercontrol module 524. In the depicted example, a high-power uplink signal202 is transmitted if an object 206 is not detected. Alternatively, alow-power uplink signal 202 is transmitted if the object 206 isdetected. The low-power can be, for example, between approximately fiveand twenty decibel-milliwatts (dBm) smaller than the high-power signalat 802. In addition to or instead of changing a power of the next uplinksignal 202, the transmission parameter 526 can specify a differentantenna within the computing device 102 or a different beam steeringangle for transmitting the next uplink signal 202 (e.g., different thanone or more antennas 124 or the beam steering angle used fortransmitting the high-power signal at 802).

At 808, the wireless transceiver 120 generates another electromagneticfield 208 to attempt to detect the object 206. By scheduling multipleelectromagnetic fields 208 over some time period, the wirelesstransceiver 120 can dynamically adjust the transmission parameter 526based on a changing environment. In some cases, the electromagneticfield 208 can be generated and sensed between active data cycles thatoccur during wireless communication or during predetermined times set bythe processor 122. By actively monitoring the environment, the wirelesstransceiver 120 can appropriately adjust the transmission parameter 526in real-time to balance communication performance with compliance orradiation requirements. This monitoring also enables the transmissionparameter 526 to be incrementally adjusted to account for movement bythe object 206. The sequence described above can also be applied toother antennas. In some cases, the other antennas and the antennas 124may generate electromagnetic fields 208 at a same time or at differenttimes.

FIG. 9 illustrates example transmission adjustments that are made inaccordance with proximity detection based on an electromagnetic fieldperturbation. In FIG. 9, the computing device 102 includes antennaarrays 216-1 and 216-2. Through the antenna arrays 216-1 and 216-2, thecomputing device 102 can communicate with the base station 104 throughmultiple signal paths 902-1 to 902-3. A first signal path 902-1represents a direct signal path between the antenna array 216-1 and thebase station 104. A second signal path 902-2 represents an indirectsignal path between the antenna array 216-1, a reflector 904, and thebase station 104. A third signal path 902-3 represents an indirectsignal path between the antenna array 216-2, the reflector 904, and thebase station 104.

In the depicted environment, a finger 906 blocks the first signal path902-1. Through proximity detection based on an electromagnetic fieldperturbation, the antenna array 216-1 can detect the finger 906. Thetransmitter control module 524 can generate transmission parameters 526for the uplink signal 202 based on the detection. In someimplementations, the transmission parameters 526 can ensure complianceor radiation requirements by specifying a different beam steering anglethat enables the uplink signal 202 to be transmitted via the antennaarray 216-1 using the second signal path 902-2 instead of the firstsignal path 902-1. The beam steering angle can decrease radiationexposure at the finger 906 by directing a main-lobe of the uplink signal202 away from the finger 906. Additionally or alternatively, a transmitpower for the uplink signal 202 can be reduced for the second signalpath 902-2 or the first signal path 902-1. In other implementations, thetransmission parameters 526 can specify a different antenna array 216for transmitting the communication signal. For example, the antennaarray 216-2 can be used instead of the antenna array 216-1 to transmitthe uplink signal 202 using the third signal path 902-3. By adjustingthe transmission parameters 526, the computing device 102 can maintaincommunication with the base station 104 while ensuring compliance.

FIG. 10 is a flow diagram illustrating an example process 1000 forproximity detection based on an electromagnetic field perturbation. Theprocess 1000 is described in the form of a set of blocks 1002-1006 thatspecify operations that can be performed. However, operations are notnecessarily limited to the order shown in FIG. 10 or described herein,for the operations may be implemented in alternative orders or in fullyor partially overlapping manners. Operations represented by theillustrated blocks of the process 1000 may be performed by a computingdevice 102 (e.g., of FIG. 1, 2, or 9), a controller 318 (e.g., of FIG.3), or a processor 122 (e.g., of FIG. 1, 5, or 6). More specifically,the operations of the process 1000 may be performed by the proximitydetection module 520 or the transmitter control module 524 of FIG. 5 or6.

At block 1002, an electromagnetic field is generated via at least oneantenna. For example, the electromagnetic field 208 of FIG. 2 can begenerated via the wireless transceiver 120 and at least one of theantennas 124. The electromagnetic field 208 can be generated with aspecific frequency, polarization (e.g., horizontal polarization orvertical polarization), phase reference, angular direction (e.g., byperforming beamforming techniques using multiple antenna elements 212 orvia a directional antenna), and so forth.

At block 1004, energy from the electromagnetic field is received via atleast two feed ports. The at least two feed ports are associated withone or more other antennas. For example, at least two portions of theelectromagnetic field 208 can be respectively sensed by at least twoantenna feed ports that are coupled to one or more other antennas 124,such as feed ports 302 and 304 of FIG. 3. The antenna feed ports can beassociated with a same antenna or with different antennas. The at leasttwo portions can include portions 306 and 308, which may representdifferent locations within the electromagnetic field 208 (e.g., via twophysically separated antenna feed ports), different phases of theelectromagnetic field 208 (e.g., via differential feed ports of a dipoleantenna 312), different polarizations of the electromagnetic field 208(e.g., via orthogonally-polarized feed ports of a patch antenna 314),different angular directions of the electromagnetic field 208 (e.g., viafeed ports of a bowtie antenna 316), a combination thereof, and soforth.

At block 1006, a transmission parameter is adjusted based on the energyreceived via the at least two feed ports. The transmission parametervaries based on a range to an object that is present within theelectromagnetic field. For example, the transmitter control module 524can adjust the transmission parameter 526 based on the energy from theelectromagnetic field 208 that is received via the feed ports 302 and304. In general, the feed ports 302 and 304 can receive or sense aperturbation 210 that can be caused by the object 206 disturbing theelectromagnetic field 208. The perturbation 210 can cause the energy ofthe electromagnetic field 208 to fluctuate at the one or more otherantennas. Example transmission parameters 526 include a transmit powerlevel, a beam steering angle, a transmission frequency, a wirelesscommunication protocol, a selected antenna, and so forth. Thus, atransmit power level, for instance, can be increased for greater rangesto the object 206 and decreased for smaller ranges to the object 206. Inthis way, transmission of the uplink signal 202 can be adjusted to meettargeted guidelines.

Unless context dictates otherwise, use herein of the word “or” may beconsidered use of an “inclusive or,” or a term that permits inclusion orapplication of one or more items that are linked by the word “or” (e.g.,a phrase “A or B” may be interpreted as permitting just “A,” aspermitting just “B,” or as permitting both “A” and “B”). Further, itemsrepresented in the accompanying figures and terms discussed herein maybe indicative of one or more items or terms, and thus reference may bemade interchangeably to single or plural forms of the items and terms inthis written description. Finally, although subject matter has beendescribed in language specific to structural features or methodologicaloperations, it is to be understood that the subject matter defined inthe appended claims is not necessarily limited to the specific featuresor operations described above, including not necessarily being limitedto the organizations in which features are arranged or the orders inwhich operations are performed.

What is claimed is:
 1. An apparatus comprising: an antenna arrayincluding at least two feed ports; and a wireless transceiver coupled tothe antenna array, wherein the wireless transceiver is configured to:generate an electromagnetic field via the antenna array; receive energyfrom the electromagnetic field via the at least two feed ports of theantenna array; and adjust a transmission parameter based on the energyreceived via the at least two feed ports of the antenna array, whereinthe transmission parameter varies based on a range to an object that ispresent within the electromagnetic field.
 2. The apparatus of claim 1,wherein the wireless transceiver is configured to transmit an uplinksignal or a proximity detection signal via the antenna array to generatethe electromagnetic field.
 3. The apparatus of claim 2, wherein theuplink signal comprises a Fifth Generation (5G) uplink signal.
 4. Theapparatus of claim 2, wherein the proximity detection signal comprises:an orthogonal frequency-division multiplexing (OFDM) signal; afrequency-modulated continuous-wave (FMCW) signal; or a continuous-wavesignal having a constant frequency.
 5. The apparatus of claim 1, whereinthe wireless transceiver is further configured to transmit an uplinksignal using the transmission parameter.
 6. The apparatus of claim 1,wherein the transmission parameter comprises at least one of thefollowing: a power level; a beam steering angle; a frequency; a selectedantenna; or a communication protocol.
 7. The apparatus of claim 1,wherein: the at least two feed ports include a first feed port and asecond feed port; the antenna array includes a first antenna element anda second antenna element, the second antenna element including the firstfeed port and the second feed port; and the wireless transceiver isconfigured to: generate the electromagnetic field via the first antennaelement; receive a first portion of the energy from the electromagneticfield via the first feed port; and receive a second portion of theenergy from the electromagnetic field via the second feed port.
 8. Theapparatus of claim 7, wherein: the second antenna element comprises apatch antenna; the first feed port of the patch antenna comprises ahorizontally-polarized feed port; the second feed port of the patchantenna comprises a vertically-polarized feed port; and the firstportion and the second portion respectively comprise ahorizontally-polarized portion and a vertically-polarized portion. 9.The apparatus of claim 8, wherein: the first antenna element comprisesanother patch antenna, the other patch antenna including anotherhorizontally-polarized feed port and another vertically-polarized feedport; and the wireless transceiver is further configured to generate atleast one of the following: a horizontally-polarized electromagneticfield via the other horizontally-polarized feed port of the firstantenna element; or a vertically-polarized electromagnetic field via theother vertically-polarized feed port of the first antenna element. 10.The apparatus of claim 7, wherein: the second antenna element comprisesa dipole antenna; the first feed port and the second feed port of thedipole antenna together comprise a pair of differential feed ports; andthe first portion and the second portion each comprise differentialportions of the electromagnetic field.
 11. The apparatus of claim 7,wherein: the second antenna element comprises a bowtie antenna; thefirst feed port and the second feed port together comprise a pair ofdirectional feed ports; the first portion and the second portion eachcomprise a different angular direction of the electromagnetic field; andthe second antenna element is adjacent to the first antenna element. 12.The apparatus of claim 1, wherein: the at least two feed ports include afirst feed port and a second feed port; the antenna array includes afirst antenna element, a second antenna element, and a third antennaelement, the second antenna element including the first feed port andthe third antenna element including the second feed port; and thewireless transceiver is configured to: generate the electromagneticfield via the first antenna element; receive a first portion of theenergy from the electromagnetic field via the first feed port; andreceive a second portion of the energy from the electromagnetic fieldvia the second feed port.
 13. The apparatus of claim 1, wherein: the atleast two feed ports include a first feed port, a second feed port, athird feed port, and a fourth feed port; the antenna array includes afirst antenna element, a second antenna element, and a third antennaelement, the second antenna element including the first feed port andthe second feed port, the third antenna element including the third feedport and the fourth feed port; and the wireless transceiver isconfigured to: generate the electromagnetic field via the first antennaelement; receive a first portion and a second portion of the energy fromthe electromagnetic field via the first feed port and the second feedport, respectively; and receive a third portion and a fourth portion ofthe energy from the electromagnetic field via the third feed port andthe fourth feed port, respectively.
 14. An apparatus comprising: anantenna array including at least two feed ports; transmission means forgenerating an electromagnetic field via the antenna array; receptionmeans for receiving energy from the electromagnetic field via the atleast two feed ports of the antenna array; and adjustment means foradjusting a transmission parameter based on the energy received via theat least two feed ports of the antenna array, wherein the transmissionparameter varies based on a range to an object that is present withinthe electromagnetic field.
 15. The apparatus of claim 14, wherein thetransmission means is configured to transmit at least one of thefollowing signals to generate the electromagnetic field: an uplinksignal; a Fifth Generation (5G) uplink signal; an orthogonalfrequency-division multiplexing (OFDM) signal; a frequency-modulatedcontinuous-wave (FMCW) signal; or a continuous-wave signal having aconstant frequency.
 16. The apparatus of claim 14, wherein thetransmission parameter comprises at least one of the following: a powerlevel; a beam steering angle; a frequency; a selected antenna; or acommunication protocol.
 17. The apparatus of claim 14, wherein: the atleast two feed ports include a first feed port and a second feed port;the antenna array includes a first antenna element and a second antennaelement, the second antenna element including the first feed port andthe second feed port; the transmission means is configured to generatethe electromagnetic field via the first antenna element; and thereception means is configured to: receive a first portion of the energyfrom the electromagnetic field via the first feed port; and receive asecond portion of the energy from the electromagnetic field via thesecond feed port.
 18. The apparatus of claim 17, wherein: the secondantenna element comprises a patch antenna; the first feed port of thepatch antenna comprises a horizontally-polarized feed port; the secondfeed port of the patch antenna comprises a vertically-polarized feedport; and the first portion and the second portion respectively comprisea horizontally-polarized portion and a vertically-polarized portion. 19.The apparatus of claim 18, wherein: the first antenna element comprisesanother patch antenna, the other patch antenna including anotherhorizontally-polarized feed port and another vertically-polarized feedport; and the transmission means is configured to generate at least oneof the following: a horizontally-polarized electromagnetic field via theother horizontally-polarized feed port of the first antenna element; ora vertically-polarized electromagnetic field via the othervertically-polarized feed port of the first antenna element.
 20. Theapparatus of claim 17, wherein: the second antenna element comprises adipole antenna; the first feed port and the second feed port of thedipole antenna together comprise a pair of differential feed ports; andthe first portion and the second portion each comprise a differentialportion of the electromagnetic field.
 21. The apparatus of claim 17,wherein: the second antenna element comprises a bowtie antenna; and thefirst portion and the second portion each comprise a different angulardirection of the electromagnetic field.
 22. A method for proximitydetection based on an electromagnetic field perturbation, the methodcomprising: generating an electromagnetic field via at least one antennaof an antenna array; receiving energy from the electromagnetic field viaat least two feed ports of the antenna array, the at least two feedports being associated with one or more other antennas of the antennaarray; and adjusting a transmission parameter based on the energyreceived via the at least two feed ports of the antenna array, thetransmission parameter varying based on a range to an object that ispresent within the electromagnetic field.
 23. The method of claim 22,wherein the generating of the electromagnetic field comprisestransmitting at least one of the following signals: an uplink signal; aFifth Generation (5G) uplink signal; an orthogonal frequency-divisionmultiplexing (OFDM) signal; a frequency-modulated continuous-wave (FMCW)signal; or a continuous-wave signal having a constant frequency.
 24. Themethod of claim 22, wherein the transmission parameter comprises atleast one of the following: a power level; a beam steering angle; afrequency; a selected antenna; or a communication protocol.
 25. Themethod of claim 22, wherein the at least one antenna comprises at leastone of the following: a patch antenna including a horizontally-polarizedfeed port and a vertically-polarized feed port; a dipole antennaincluding differential feed ports; or a bowtie antenna includingdirectional feed ports.
 26. The method of claim 25, wherein thegenerating of the electromagnetic field comprises at least one of thefollowing: generating, based on the at least one antenna comprising thepatch antenna, the electromagnetic field via at least one of thehorizontally-polarized feed port or the vertically-polarized feed port;generating, based on the at least one antenna comprising the dipoleantenna, the electromagnetic field via at least one of the differentialfeed ports; or generating, based on the at least one antenna comprisingthe bowtie antenna, the electromagnetic field via at least one of thedirectional feed ports.
 27. The method of claim 22, wherein: the one ormore other antennas comprise a first antenna; and the first antennacomprises at least one of the following: a patch antenna including ahorizontally-polarized feed port and a vertically-polarized feed port; adipole antenna including differential feed ports; or a bowtie antennaincluding directional feed ports.
 28. The method of claim 27, wherein:the at least two feed ports are associated with the first antenna; andthe receiving of the energy via the at least two feed ports comprises atleast one of the following: receiving, based on the first antennacomprising the patch antenna, the energy via the horizontally-polarizedfeed port and the vertically-polarized feed port; receiving, based onthe first antenna comprising the dipole antenna, the energy via thedifferential feed ports; or receiving, based on the first antennacomprising the bowtie antenna, the energy via the directional feedports.
 29. The method of claim 27, wherein: the one or more otherantennas comprise a second antenna; the at least two feed ports includea first feed port and a second feed port, the first feed port beingassociated with the first antenna, and the second feed port beingassociated with the second antenna; and the receiving of the energy fromthe electromagnetic field comprises: receiving a first portion of theenergy via the first antenna; and receiving a second portion of theenergy via the second antenna.
 30. The apparatus of claim 1, wherein thewireless transceiver is further configured to determine that the objectis present within a detectable range of the wireless transceiver basedon the energy received via the at least two feed ports of the antennaarray, and wherein a duration for which the electromagnetic field isgenerated via the antenna array is based on the detectable range of thewireless transceiver.